V. Yanovsky

Flux growth and characteristics of some ferroelectric and related crystals

Single crystals of 38 ferroelectrics and related compounds: Bi2WO6, Ln2WO6 and Ln2MoO6 (Ln = La-Lu, Y), RNbW2O9 (R = K, Rb), RNbWO6 (R = K, Rb, Tl), Al2(WO4)3, Dy2(MoO4)3, LiNbO3 and KNbO3 have been flux grown. The crystallization was carried out from high temperature solutions of oxide systems including the required components. High-temperature microscopy was used for choosing the starting solution compositions and temperature conditions. Crystal growth was initiated by spontaneous nucleation during slow cooling of the solution. Only KNbO3 crystals were grown on (100) KNbO3 seeds. The composition, morphology, domain structure, optical, dielectric and other characteristics of the crystals have been studied. Bi2WO6 and LiNbO3 crystals grown at temperatures below the ferroelectric transition point were single domain. The morphology of Bi2WO6 crystal reflected their polar structure.

Peak-effect, scaling behavior and voltage-current characteristics for TmBa2Cu3O7−δ single crystal

Abstract The peak-effect in the nearly untwinned TmBa 2 Cu 3 O x single crystal has been studied. Two magnetic field intervals corresponding to different behaviors of shielding currents j s were found. The current-voltage characteristics extracted from the magnetization measurements are described by the powerlike relation E ∼ j s n with n being dependent on temperature and magnetic field. Possible reasons of the observed behavior are discussed.

Ferroelectrics with the structure of hexagonal tungsten bronze type

Synthesis, crystal growth, and characterization of some compounds AB3O9 with the structure of hexagonal tungsten bronze (HTB) type were carried out. A study of dielectric, optical, and other features of KNbW2O9 and RbNbW2O9 single crystals shows that they undergo diffuse ferroelectric phase transitions in the temperature regions 560-600°C and 750-800°C, respectively. Ferroelectric properties are also expected in case of many other compounds of this family.

The critical current and magnetization anisotropy in TmBa2Cu3Ox and Bi2Sr2CaCu2Oy single crystals

Abstract The relations between critical current and magnetisation were derived for anisotropic superconductors The critical current and magnetisation anisotropy for TmBa2Cu3Ox and Bi2Sr2CaCu2Oy single crystals was studied.